Bike theft is one of the most disheartening experiences a cyclist can face — and it’s far more common than most people realise. In major cities, hundreds of thousands of bikes are stolen every year, with the vast majority never recovered. The single most effective thing you can do to protect your bike is invest in the right lock and use it correctly.
This guide cuts through the marketing noise to give you an honest assessment of bike lock security ratings, the real-world performance of different lock types, and the best strategies for protecting your bike — whether you’re locking up for two minutes or overnight. We also cover the lock combinations used by professional bike couriers, commuters, and cycling advocates who’ve thought hard about this problem.
Understanding Bike Lock Security Ratings
Most quality bike locks are rated by independent security organisations. The two most widely recognised rating systems are:
Sold Secure (UK)
Sold Secure is an independent testing body that rates locks as Bronze, Silver, Gold, or Diamond. Their testers attempt to defeat locks using real-world tools — bolt cutters, angle grinders, freeze spray, and more — under timed conditions. A Gold rating means a lock resisted tools for a meaningful period; Diamond is the highest standard and indicates the lock performed against heavy-duty angle grinders.
ART (Netherlands)
The ART Foundation uses a star system (1–5 stars) to rate bike locks in Europe. Many insurance companies require a certain ART rating for coverage to apply to bicycle theft, so if you’re insuring an expensive bike, check what rating your insurer requires before buying.
The Kryptonite Scale
Kryptonite — one of the most well-known lock brands — uses its own 1–10 security scale across its product range. While useful for comparing locks within the Kryptonite range, it shouldn’t be used to compare across brands.
The Main Types of Bike Lock
U-Locks (D-Locks)
U-locks are the most widely recommended lock type for everyday security. A rigid U-shaped bar threads through your frame and wheel, then locks into a crossbar. The small internal space of a quality U-lock makes it very difficult for thieves to insert a jack or get leverage for bolt cutters.
Top picks:
- Kryptonite Evolution Series 4: An excellent mid-range U-lock (Sold Secure Gold) that balances security and weight. The 4″ model is harder for thieves to work with due to its small internal space.
- Kryptonite New York Fahgettaboudit: One of the most secure U-locks available (Sold Secure Diamond). Heavy, but the go-to choice for high-crime urban environments.
- Hiplok DX: A strong Sold Secure Gold U-lock with a convenient hip carry system — popular among commuters.
- Abus Granit X-Plus 54: Excellent German engineering, Sold Secure Gold, and a compact form factor. Very resistant to picking and drilling.
Chain Locks
Chain locks offer more flexibility than U-locks — you can loop them around larger objects and awkward anchor points that a rigid U-lock can’t reach. However, they’re only as strong as their weakest link (typically the padlock), and heavy chains add significant weight.
Top picks:
- Kryptonite New York Chain 1210: Sold Secure Diamond rated, this is one of the most secure chain locks available. At 10mm links, it resists all but the most determined angle grinder attacks.
- Hiplok Gold Chain: A well-balanced chain lock with a sleeved chain (protecting the bike’s finish) and Sold Secure Gold rating, at a more manageable weight than the Kryptonite option.
- Abus City Chain X-Plus 1060: Elegant, effective, and Sold Secure Gold. Good padlock included.
Folding Locks
Folding locks fold into a compact package, making them easy to store in a jersey pocket, bag, or mount bracket on the frame. They’re more versatile than U-locks (can wrap around larger anchor points) while being more portable than chain locks. Their security is generally good, though dedicated angle grinder attacks can defeat them faster than the best U-locks or chains.
Top picks:
- Abus Bordo Granit XPlus 6500: Sold Secure Gold, extremely compact when folded, and very robust hinge design. The benchmark folding lock.
- Kryptonite Kryptolok 610 Folding: A more affordable option with good security credentials and a neat frame mount included.
Cable Locks
Cable locks are not recommended as a primary lock. Even heavy-gauge cables can be defeated with bolt cutters in seconds. Use a cable lock only as a secondary lock alongside a U-lock or chain, to secure a wheel or saddle that your primary lock doesn’t reach.
The Two-Lock Strategy
The gold standard for urban bike security is using two different types of lock simultaneously. Here’s why: thieves typically carry one type of tool. If they have bolt cutters that defeat a chain, they likely don’t also have an angle grinder for your U-lock. Using two lock types means they’d need two different attacks — which takes more time, more noise, and more risk of being seen.
The classic combination is a quality U-lock securing the frame and rear wheel to an anchor point, plus a chain or cable threading through the front wheel and back to the frame. This secures all three contact points — frame, rear wheel, front wheel — to an immovable object.
How to Lock Your Bike Correctly
Even the best lock can be defeated if it’s used incorrectly. Here are the critical principles:
- Always lock to something immovable. Bike racks, dedicated cycle parking, and thick metal posts are good. Street signs can sometimes be lifted out of the ground. Thin railing can be cut.
- Fill the U-lock. A U-lock with lots of empty internal space gives thieves room to insert a bottle jack and break the lock. Use the smallest U-lock that still fits around your frame, rear wheel, and anchor point.
- Keep the lock off the ground. Locks on the ground can be attacked with a hammer and chisel (cold cracking) or frozen with liquid nitrogen. Keep the keyhole facing downward but the shackle elevated.
- Lock the frame AND a wheel. The frame is the most valuable part of the bike. Never lock only a wheel — a thief will simply remove the wheel and take the rest.
- Remove quick-release components. Take your saddle, lights, computer, and any quick-release wheels with you if leaving the bike for an extended period.
Budget-Friendly Security Options
Security doesn’t have to be expensive. If you’re riding a budget bike or just getting started, a Sold Secure Silver rated U-lock (such as the Kryptonite KryptoLok Series 2 or Abus Bordo Lite 6050) provides meaningful deterrence at an affordable price point.
For more on maximising your cycling budget, see our guides to cycling on a budget and buying a used bike — both of which include sections on appropriate lock budgets for bikes at different price points.
Bike Theft Prevention Beyond the Lock
- Register your bike: Bikeregister, Bike Index, and similar services create a searchable database of stolen bikes linked to frame serial numbers. Register your bike’s serial number today.
- Record identifying information: Photograph your bike from multiple angles and note the frame serial number (usually stamped under the bottom bracket). Store this somewhere accessible.
- Consider GPS tracking: Devices like the Apple AirTag (hidden in a handlebar plug or saddle) or dedicated cycling trackers (Boomerang, Sherlock) can help police recover a stolen bike.
- Vary your locking location: Thieves observe patterns. If you lock in the same place every day, you may be scouted. Mix up your locations where possible.
- Insurance: For expensive bikes, specialist cycling insurance is worth the cost. Providers such as Laka, Velosure, and Bikmo offer comprehensive cover including theft — worth pairing with a quality lock rather than replacing it.
Final Thoughts
No lock is completely theft-proof — given enough time and the right tools, any lock can be defeated. The goal is to make stealing your bike harder, slower, and riskier than stealing someone else’s. A Sold Secure Gold rated U-lock used correctly, combined with smart locking habits and basic registration, puts your bike in a significantly better position than the vast majority of bikes on any rack.
Invest in good security before you need it. Replacing a bike you love is expensive, stressful, and rarely fully compensated even with insurance. The cost of a quality lock is trivial compared to the cost — financial and emotional — of having your bike stolen.
